The invention relates to a gear transmission for driving a printing press with a plurality of gear pairs formed of mutually meshing gearwheels disposed operationally in a power-flow, at least one of the gear pairs being more heavily loaded than the rest thereof during operation, and also a printing press equipped with the gear transmission.
A gear transmission of the type referred to at the introduction hereto has become known heretofore from the state of the art as exemplified by the published German Patent Document DE 41 36 195 C1, which describes a sheet-processing rotary printing press having printing units formed by printing unit cylinders disposed one after the other in series or tandem, driving power therefor being introduced via a so-called driving printing unit within the series of printing units. The printing units are driven with the aid of a continuous gear train that is made up of gearwheels fixed to the respective printing cylinders against relative rotation therewith. In the driving printing unit, a drive pinion meshes with a selected gearwheel within the train of gears.
At the selected gearwheel, the power supplied through the drive pinion is operationally divided into a part supplying a preceding number of printing units in the series, and a part supplying a number of printing units succeeding the preceding number of printing units in the series. A gear pair formed by the selected gearwheel and the drive pinion is therefore subject to higher operational loads than the remaining gearwheels.
Up to a certain limiting value for the power required to be supplied, a gear transmission of the foregoing general type can be lubricated by low-viscosity grease. All that is required therefor is a metering device for the low-viscosity grease, and devices for collecting the quantities thereof which drip off. If the amount of power to be supplied exceeds a given value, however, adequate lubrication cannot be guaranteed using low-viscosity grease. In this case, resort must be had to a circulating-oil lubricating system. This is associated with considerable construction outlay since the lubricating oil must be channelled in closed spaces. According to the state of the art, this is effected by forming the side components bearing the printing cylinders as box-shaped side walls which oil-sealingly surround the gearwheel train as has become known, for example, from the published German Patent Document DE 32 24 267 A1. This is associated in particular with a relatively high outlay or expense in the casting-technology field in order to solve the problem of mutual sealing and mutual arrangement of the succeeding or consecutive side walls, as can be seen, for example, from Patent No. 123 793 of the former German Democratic Republic.
It is accordingly an object of the invention to provide a gear transmission for driving a printing press, that is of the type described at the introduction hereto, that reduces the outlay necessary for providing adequate lubrication, for the case wherein an application or injection of a relatively high driving power makes a circulating-oil lubricating system necessary.
With the foregoing and other objects in view, there is provided, in accordance with a first aspect of the invention, a gear transmission for driving a printing press, with a plurality of gear pairs formed of mutually meshing gearwheels disposed operationally in a power-flow, at least one of the gear pairs being more heavily loaded than the rest thereof during operation, comprising a case wherein the gearwheels forming the at least one, more heavily loaded gear pair are enclosed, the rest of the gear pairs being disposed outside the case.
In accordance with another feature of the invention, the gearwheels forming the at least one, more heavily loaded gear pair are a drive pinion and a driving gear.
In accordance with a further feature of the invention, the gearwheels include a drive pinion and two coaxial driving gears fixed together against rotation relative to one another, the case enclosing the drive pinion and a first one of the two driving gears meshing with the drive pinion.
In accordance with an added feature of the invention, a second of the two driving gears is a component of a gear train that includes the rest of the gearwheels.
In accordance with a concomitant aspect of the invention, there is provided a printing press with a gear transmission for driving the printing press, the gear transmission having a construction including one or more of the foregoing features.
In this way, it is possible to realize a circulating-oil lubricating system for lubricating the more highly or heavily loaded gear pair, the lubricating system being effective only for this gear pair. The outlay for ensuring adequate lubrication under conditions wherein a relatively high drive power is supplied is thus reduced considerably compared with that of the state of the art described hereinabove. With the relatively low outlay described at the introduction hereto, a low-viscosity grease lubricating system can be provided for the less loaded gearwheels arranged outside the case, whereas an oil bath for lubrication of the more highly loaded gear pair is provided simply inside a single case, which represents a fractional part of the box-shaped side walls heretofore known in the state of the art. In this regard, appropriate sealing of the case provided in accordance with the invention also prevents mixing of the different lubricants which are used. The measures for attaining a seal of this type are therefore limited to a negligibly small area in comparison with the box-shaped side wall provided according to the state of the art.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a gear transmission for driving a printing press, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: